JP2000076732A - Recording medium having magnetic layer and optical recording layer and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the splashing of optical recording layer components, to improve the durability of a head and to enable a higher density and higher speed access by providing the surface of a base with an optical recording layer, an intermediate layer and a magnetic layer in this order. SOLUTION: This recording medium is provided with the optical recording layer, the intermediate layer and the magnetic layer in this order on the base. Recording and reproducing to and from the optical recording layer are executed through the base as the structure to hold the optical recording layer via the intermediate layer. Such layer constitution is produced by preparing coating materials for forming the respective layers and successively applying these coating materials on the base. More preferably, the formation of these coating materials at one time by a simultaneous double layer application system is made possible. The thickness of the magnetic layer is reduced to a small thickness by the simultaneous double layer application by disposing the intermediate layer between the magnetic layer and optical recording layer. The recording medium may thus be provided with the uniform magnetic layer of <=0.5 μm in reproduction thickness loss. Since the magnetic layer may be formed thin in the manner described above, information signals are preferably recorded on the magnetic layer and servo signals on the optical recording layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording medium having a magnetic layer and an optical recording layer, and more particularly to a recording medium capable of recording and reproducing a large amount of information.

[0002]

2. Description of the Related Art Information recording tapes include magnetic recording tapes,
In optical recording tapes, information recording and servo signals such as position signals are performed on a part of the recording surface in each tape. Also, various media have been developed as optical information recording media for recording or reproducing information by irradiation with laser light.
In these, information recording and servo signal recording are performed on the same recording layer. The tracking position signal is performed by a groove or a tracking servo signal, and a focus servo signal is recorded for focusing laser light. These may be the same pit. Optical recording is particularly excellent for high-speed transport of tapes. Further, an optical recording medium suitable for recording a larger amount of information than these disc-shaped recording media has been proposed (Japanese Patent Laid-Open Nos. 1-286130 and 4-163).
No. 736, No. 4-163737, No. 6-89
Nos. 464, 6-73958 and 6-251.
425, etc.).

[0003] An optical recording medium for recording or reproducing information by irradiating such a laser beam usually comprises a disc-shaped substrate or a tape-shaped support on which a dye or the like for absorbing the laser beam is mainly used. An optical recording layer is formed, and a signal recording pattern (so-called pit or mark) is formed on the optical recording layer by modulating a signal of the laser beam and condensing the signal on the optical recording layer.

[0004] Reproduction of recorded information is performed by detecting a difference in reflectance between a signal recording pattern portion and a portion where no signal recording pattern is formed.

[0005] Such an optical recording medium, like a magnetic recording medium or the like, can have a narrow track pitch, and can perform high-density recording and high-speed signal detection. These conventional optical information recording media include an infrared laser having a wavelength of 780 nm or a red laser having a wavelength of 630 nm, and a wavelength of 410 n.
m blue laser is used

On the other hand, in the case of a magnetic recording medium, for example, when the track width is reduced, when the magnetic recording medium deviates from a running position, or when the support expands and contracts due to environmental changes such as temperature and humidity, the reproducing head can read data. Since the vehicle runs off the optimal position of the track on which is recorded, the output is likely to decrease. Therefore, recently, similarly to the above optical recording medium, a servo signal is recorded on a magnetic layer of a magnetic recording medium, and the relative position of the head is detected based on the servo signal so that the head can move at an optimum position on a track. A method of controlling is used.

However, in this method, the recording density is reduced by the number of tracks of the servo signal to the magnetic layer side, and further, when the servo is written using magnetism, clogging of the head tends to occur. There's a problem. In addition, when a signal recording pattern is formed on the optical recording layer, there is a problem that components of the optical recording layer are scattered, the head is soiled, and the magnetic output is reduced.

[0008]

SUMMARY OF THE INVENTION According to the present invention, when a signal recording pattern is formed on an optical recording layer, the scattering of the components of the optical recording layer is prevented, the durability of the head is improved, and the density is increased. An object of the present invention is to provide a recording medium capable of high-speed access.

[0009]

The present invention is a recording medium characterized in that an optical recording layer, an intermediate layer and a magnetic layer are provided on a support in this order. Further, the present invention is the above-mentioned method for producing a recording medium, comprising applying a coating material for forming an optical recording layer, a coating material for forming an intermediate layer, and a coating material for forming a magnetic layer on a support.

[0010] In the recording medium of the present invention, the method of forming each of the above layers is not particularly limited.
Although a sputtering method, a coating method, and the like are applied or used in combination, it is preferable to use at least a coating method from the viewpoint of productivity. Preferred embodiments of the present invention are as follows. 1 A recording medium having a back coat layer on the opposite side of a support provided with an optical recording layer and the like.

(2) The magnetic layer has an average particle diameter of 0.1 to 1 μm.
A recording medium comprising m diamonds. 3. A recording medium wherein an information signal is recorded on a magnetic layer, a servo signal is recorded on an optical recording layer, and a tracking servo signal is detected by scanning in a width direction of the optical recording layer.

According to the present invention, an optical recording layer, an intermediate layer and a magnetic layer are provided on a support in this order, and the optical recording layer is sandwiched between the magnetic layer and the support via the intermediate layer. Recording and reproduction on the optical recording layer are performed through the support. Further, the layer constitution of the present invention can be produced by preparing each coating material for forming a layer, and sequentially applying these coating materials on a support. And, preferably,
There is an advantage that these paints can be formed at once by a simultaneous multilayer coating method.

In the present invention, if an information signal is recorded on the magnetic layer, a servo signal needs to be recorded on the optical recording layer, and vice versa. In particular, in the present invention, since an intermediate layer is provided between the magnetic layer and the support, the magnetic layer can be made thin. Therefore, it is preferable that information signals be recorded on the magnetic layer and servo signals be recorded on the optical recording layer.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The thickness of the magnetic layer of the recording medium of the present invention is usually 0.05-2 .mu.m, preferably 0.07-1.
5 μm, more preferably 0.1 to 1.0 μm, and the thickness of the optical recording layer is usually 0.05 to 1 μm, preferably 0.1 to 0.8 μm, more preferably 0.2 to 0.5 μm.
m. By setting these thickness ranges,
The contact between the recording medium and the head is improved, and head clogging does not occur.

The ferromagnetic metal powder contained in the magnetic layer of the present invention containing alumina and / or silica in the surface layer has high coercive force and excellent recording density. The average major axis length of the ferromagnetic metal powder is 0.3 μm or less, and the specific surface area is 40 m.
^It is preferably at least ² / g. In the present invention, since the intermediate layer is provided between the magnetic layer and the optical recording layer, the thickness of the magnetic layer can be reduced by simultaneous multi-layer coating to provide a uniform magnetic layer having a reproduction thickness loss of 0.5 μm or less.

As the binder for the intermediate layer, those used for the magnetic layer can be used. In the above-mentioned intermediate layer, the filler may not be used, but the one used for the magnetic layer can be used. As the filler, preferably, titanium oxide, barium sulfate, crushed alumina, spherical alumina, needle-like alumina, calcium carbonate, silica, α-iron oxide (including needle-like, spindle-like, and spherical) is used. Titanium oxide and α-iron oxide are preferred. The filler having an average particle size of 0.01 to 1 μm can be used. The filler / binder ratio is preferably from 1/20 to 20/1 by weight. The structure of the optical recording layer is not particularly limited as long as the above function is achieved.
It can have an inorganic compound such as rNx or an organic dye such as cyanine. The inorganic compound can be provided on the support by vapor deposition or the like. Further, the organic dye can be provided on the support by coating alone or together with a binder.

As the binder used for the optical recording layer, a cellulose resin such as cellulose acetate butyrate or nitrocellulose is preferable for achieving high sensitivity of the optical recording layer. This is because the pit opening becomes highly sensitive to light irradiation with a laser or the like. As the support, polyester, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), aramid, polyimide, or the like can be used. When a tape-shaped recording medium having a small total thickness is desired, PEN and aramid are preferred.

The surface roughness of the support is preferably 5 nm or less in terms of the center plane average surface roughness (Ra) on both surfaces. Ra is MPO using TOPO3D manufactured by WYKO.
It is determined by measuring in an area of about 250 μm × 250 μm by the IRAU method. Spherical correction and cylindrical correction are added at a measurement wavelength of about 650 nm. This method is a non-contact surface roughness meter that measures by light interference.

The MD (longitudinal direction) of the support and the TD
The F5 value in the (width direction) is preferably from 8 to 15 kg / mm ² . The heat shrinkage of MD and TD of the support is 0.1 to 0.6.
% Is preferred. The thickness of the support is preferably 1 to 20 μm. Further, when a back coat layer is provided on the surface opposite to the surface of the support on which the magnetic layer, the optical recording layer and the like are provided, running durability is improved.

[0020] The thickness of the back coat layer is preferably 0,1.
It is in the range of 1-2 μm. Also, when diamond particles having an average particle diameter of 0.1 to 1 μm are contained as an abrasive in the magnetic layer, the output is improved by increasing the filling of the ferromagnetic metal powder, the head polishing is improved, and the running durability is also improved. I do. The diamond particles are preferably 1 to ferromagnetic metal powder.
-20% by weight.

When writing servo signals to the optical recording layer, writing is performed by a laser array (parallel), single (one),
Various things such as multi (plural) types are possible. The tracking servo signal is a signal for determining the position of the magnetic signal, and the focus servo signal is a signal for determining the height to a pit for tracking.
The height of the pit is determined by the focus servo, and the tracking determines the position.When scanning the pits in the longitudinal direction, a method of tracing the maximum area of the pits and obtaining the optimum value, or the method of pitting at a certain scan angle The method for detecting the maximum area value of the signal is not particularly limited.

In the present invention, the tracking servo signal is preferably detected by scanning in the width direction of the optical recording layer.
This is because, for example, control using a semiconductor laser rotating in the width direction of the recording medium can process a large number of information signals at a time. The total thickness of the recording medium of the present invention,
Preferably it is less than 10 μm. Reducing the thickness is preferable for improving the recording density, particularly the recording volume density.

Hereinafter, the present invention will be described in more detail. First, the optical recording layer will be described. The case where an organic dye is used as a dye that can be included in the optical recording layer will be described below, but the function is the same when an inorganic dye is used.
Dyes exhibit an absorption spectrum capable of absorbing light used for signal recording, for example, cyanine dyes, merocyanine dyes, oxonol dyes, azomethine dyes, azo dyes, phthalocyanine dyes, and metals having these dye structures as ligands There are complexes and the like, and at least one kind can be used. Specific examples of these dyes include compounds of the following formula (a).

[0024]

Embedded image

In the formula (a), R ₁ represents 1 to 10 carbon atoms.
And X represents a counter anion. For example,
Cl ⁻ , ClO ₄ ⁻ , Br ⁻ , BF ₄ ⁻ , CF ₃ SO ₃
^-, and the like. n is an integer of 0-4. Particularly, as R ₁ , for example, a methyl group, an ethyl group, an n-butyl group,
Examples include an isobutyl group and a 2-ethylhexyl group.
In particular, those in which R ₁ is an n-butyl group are preferable because of high solubility and easy preparation of a coating solution. Further, in the formula (a), when n is the following value, it is effective when using lasers having the following wavelengths. Hereinafter, a case where laser light is used will be described.

N = 0 wavelength 423 ± 25 nm n = 1 wavelength 557 ± 25 nm n = 2 wavelength 650 ± 25 nm n = 3 wavelength 758 ± 25 nm

The optical recording layer contains the above-mentioned dyes appropriately selected in response to a laser beam to be responsive. For example, when forming an infrared-sensitive optical recording layer that is sensitive to infrared light, the compound is one in which n in the formula (a) is 3. When forming a red-sensitive optical recording layer, n in Formula (a) is 2
Is a compound. Further, when forming a blue-sensitive optical recording layer, it is a compound in which n in formula (a) is 0.

The optical recording layer preferably contains these dyes as a solid dispersion. Here, the solid dispersion may be referred to as a pigment dispersion. Generally, in a dye solution, a dye compound exists as an isolated molecule in a medium such as a solvent. In a solid dispersion, fine solids (microcrystals) of a dye are suspended or dispersed in the medium. The difference between the two can be determined, for example, by the presence or absence of diffraction due to the regular molecular arrangement in the crystal when irradiated with X-rays.

In the present invention, when the size of the dye dispersed as a solid dispersion in the optical recording layer becomes larger than the laser beam used for recording information, noise increases. It is important not to include particles of a particle size.

The polymer compound contained as a binder in the optical recording layer of the recording medium of the present invention does not substantially absorb laser light used for recording information, and the dye or the anti-fading agent is used. It is used to facilitate maintaining an amorphous state without crystallization. Examples of such polymer compounds include natural polymer substances such as gelatin, dextran, rosin, rubber, cellulose or nitrocellulose, diacetylcellulose, cellulose acetate, cellulose derivatives such as cellulose acetate butyrate, polyethylene, polystyrene, and polypropylene. ,
Hydrocarbon resins such as polyisobutylene, polyvinyl chloride, polyvinylidene chloride, vinyl resins such as polyvinyl chloride-polyvinyl acetate copolymer, polyacrylamide,
Acrylic resin such as polymethyl acrylate, polymethyl methacrylate, polyvinyl alcohol, chlorinated polyolefin, polyimide or polyimide acid which is a partial decay product thereof, polystyrene, epoxy resin, butyral resin, rubber derivative, phenol-formaldehyde resin, etc. Synthetic polymer substances such as an initial polymer of a thermosetting resin can be used.

In the recording medium of the present invention, the content of the dye / binder in the optical recording layer is usually 0.1% by weight.
It is in the range of 1-100, preferably in the range of 0.5-20. In general, the amount of light energy absorbed in the optical recording layer increases as the content of the dye increases. When the amount of the binder increases, the film thickness increases, the energy required to deform the optical recording layer at the time of recording information increases, and the sensitivity decreases. Alternatively, as the film thickness increases, the smoothness of the coating film decreases and noise increases. Therefore, the amount of the binder is preferably as small as possible as long as the fixation of the dye is not impaired, so that the weight ratio of the dye / binder is preferably in the above range. In the infrared-sensitive optical recording layer, the content ratio of the dye / binder is preferably in the range of 0.5 to 10. In the red-sensitive optical recording layer, the content ratio of the dye / binder is preferably in the range of 0.5 to 20. Further, in the blue-sensitive optical recording layer, the content ratio of the dye / binder is preferably in the range of 1 to 20.

It is preferable to add a singlet oxygen quencher to the optical recording layer for the purpose of preventing photo-bleaching of the dye contained in the optical recording layer. Examples of the singlet oxygen quencher include quenchers described in U.S. Pat. No. 4,999,281 and JP-A-59-178295, and aminium compounds described in JP-A-6-318772. And the like.

In the recording medium of the present invention, when an information signal is recorded on the optical recording layer, the recording medium preferably has two or more optical recording layers, and has at least one intermediate layer between the optical recording layers. preferable. This intermediate layer has a role of preventing deformation of pits, which are information recording units, by a laser beam used for recording or reproducing information. Incidentally, this intermediate layer is different from the intermediate layer provided between the magnetic layer and the optical recording layer in the present invention. However, since the latter intermediate layer can also fulfill the above function, the optical recording layer is It is particularly advantageous to provide a single layer.

When the recording medium of the present invention has both a blue-sensitive optical recording layer and an infrared-sensitive optical recording layer, an intermediate layer is arranged below the blue-sensitive optical recording layer to record or reproduce information. In order to prevent the infrared-sensitive optical recording layer below the blue-sensitive optical recording layer from being sensitive to the blue laser incident on the blue-sensitive optical recording layer, it is effective to combine the role of a yellow filter with the intermediate layer. It is.

Materials for forming the intermediate layer include a binder, a low melting point oily substance, a dye, a pigment and the like.
In particular, when the intermediate layer has a role of a yellow filter, it preferably contains a yellow dye.

The thickness of the intermediate layer is usually from 0.05 to
It is 0.2 μm, preferably 0.1 to 0.2 μm. In order to prevent pit deformation, an intermediate layer having a thickness of 0.05 μm or more is preferable. When a red-sensitive optical recording layer is provided as a lower layer, the red sensitivity of the red-sensitive optical recording layer is reduced. In order not to cause this, the thickness of the intermediate layer is preferably 0.2 μm or less.

When the recording medium of the present invention has a blue-sensitive optical recording layer, the blue-sensitive optical recording layer is the uppermost layer,
It is preferable that a green-sensitive optical recording layer, a red-sensitive optical recording layer, and / or an infrared-sensitive optical recording layer are laminated thereunder via an intermediate layer. In particular, in the case of a recording medium having a blue-sensitive optical recording layer, a green-sensitive optical recording layer, a red-sensitive optical recording layer, and an infrared-sensitive optical recording layer, the blue-sensitive optical recording layer is the uppermost layer. It is preferable that a layer structure in which a green-sensitive optical recording layer, a red-sensitive optical recording layer, and an infrared-sensitive optical recording layer are laminated in this order through an intermediate layer having a role of a yellow filter.

In the recording medium of the present invention, the center plane average surface roughness (Ra) of the surface of the uppermost optical recording layer is required to have high smoothness in order to prevent scattering of recording / reproducing light.
Usually, it is 1 to 500 nm, preferably 1 to 30 nm.

Generally, the reflected light used for recording or reading information is light in which the reflection from the incident surface and the reflection from the support surface are overlapped. Therefore, they interfere with each other depending on the wavelength of light and the film thickness. Therefore, when the optical recording layer is deformed by irradiating a laser beam, if the relationship of the interference changes greatly, the signal strength is preferably increased. Therefore, when the thickness of the layer is an integral multiple of １ ／ n (where n is the refractive index of the optical recording layer) of the wavelength of the laser beam used for recording or reading information, for example, when an infrared laser is used, If the wavelength of the infrared ray is set to about ７ of about 780 nm, a change in light interference due to the deformation of the recording layer becomes large. Therefore, the thickness of the recording layer is preferably set to 50 to 250 nm. In addition, it is not so thick, and it is preferable that the thickness is as thick as it is easy to impart smoothness. In the case of a red-sensitive optical recording layer, preferably 40 to
200 nm. In the case of a blue-sensitive optical recording layer, the thickness is preferably 30 to 150 nm.

In the recording medium of the present invention, heat generated at the time of recording information or the like is used for deformation of the optical recording layer and the adjacent layer (including thermal decomposition of dye). It is preferable that the thermal conductivity of the component is low because heat is used effectively. In general, air has lower thermal conductivity than solids, and thus, if no protective layer is provided, heat utilization efficiency is higher and recording sensitivity is higher. However, a protective layer may be provided as the uppermost layer outside the optical recording layer in consideration of mechanical strength such as scratch resistance. As a material of the protective layer, a polymer such as cellulose ester, vinylidene chloride, polyvinyl chloride, norbornene, acrylic, polycarbonate, polyvinyl alcohol, and gelatin can be used. Further, for the purpose of improving the slipperiness, a polymer containing silicon or fluorine, a surfactant, or inorganic compound particles such as calcium carbonate and silicon dioxide may be contained.

In the recording medium of the present invention, the protective layer needs to have high smoothness in order to prevent scattering of the recording / reproducing light.
0 nm, preferably 0.1 to 30 nm.

In the recording medium of the present invention, the support is not particularly limited as long as it has a disk or tape shape and can form an optical recording layer on one surface. As the disk-shaped support (disk), one having excellent dimensional stability is desirable. Generally, those made of polycarbonate, polyolefin, polymethyl methacrylate, polyacrylonitrile, polyethylene terephthalate, polyethylene naphthalate, glass, aluminum, titanium alloy, etc. having a thickness of about 0.05 to 10 mm, preferably about 0.5 to 1.5 mm. No.

In the recording medium of the present invention, each optical recording layer
Lubricants, dispersants, antistatic agents, surface treatment agents, light-blocking agents, antioxidants, fungicides, or carbon black Various additives that are added to a layer formed on a general optical recording medium may be added.

The tape-shaped support preferably has excellent flexibility and dimensional stability, and is preferably made of polyester (eg, polyethylene terephthalate, polyethylene naphthalate, polycarbonate), polystyrene, or aramid. Also, a metal foil such as copper, or a material obtained by depositing or plating a metal such as aluminum on a polymer film can be used.

In addition, since these supports are required to have high smoothness in order to prevent scattering of recording / reproducing light, the center surface roughness Ra of the support surface is preferably 5 nm or less.

Further, among the recording media of the present invention, the tape-shaped recording medium may have a back coat layer in order to ensure the running property of the medium. The backcoat layer is formed arbitrarily within a range where light can be recorded and reproduced on the optical recording layer via the support. For example, as a material for forming the back coat layer, a resin in which conductive particles are dispersed,
Examples include a conductive polymer. The back coat layer is
Preferably, it is composed of two layers, one of which is an antistatic layer provided in contact with the support, and the other is a protective layer. As the antistatic layer, an electron conductive metal oxide (for example, tin oxide, antimony oxide, vanadium pentoxide, or the like) or a conductive polymer (for example, polypyrrole, polyacetylene, or polyaniline) can be used. Further, as the polymer binder, the polymer compound used in the above-described protective layer of the optical recording layer can be used. The thickness of the back coat layer is preferably adjusted so as to offset the curl on the optical recording layer side in order to keep the shape of the recording medium flat according to the temperature and humidity conditions.

Further, it is preferable to form a layer containing a specific fluorine-containing compound on the back coat layer. This is because various types of rubber (for example, emulsion dust, cartridge dust, equipment wear dust, and the like) are likely to be generated when the tape-shaped recording medium is cut and when the recording medium runs. If such dust adheres to the back surface of the tape-shaped recording medium, it causes a signal input / output failure. Therefore, the fluorine-containing compound is used for the purpose of suppressing the dust generated in this way from adhering to the surface of the tape-shaped recording medium.

The fluorine-containing compound is preferably a compound containing at least three or more fluorine atoms, and is preferably a surfactant or a polymer.
As the fluorine-containing compound, a compound containing a nonionic, anionic, cationic, or betaine hydrophilic substituent is preferred, and a fluorine-containing compound containing an anionic substituent is particularly preferable.

Further, the recording medium of the present invention may have a reflection layer between the optical recording layer and the support. This reflective layer may be made of a metal such as gold or aluminum, or may be made of an organic compound as described in JP-A-4-3345. Further, a reflective layer may be formed by laminating layers of materials having different refractive indices, or a reflective layer made of a nonmetallic dye as described in JP-A-2-2088863. Among these, a metal reflective film is preferable in terms of manufacturing cost or in that there is no fear of mixing with other layers. As the material, aluminum which can be easily installed by vapor deposition and is inexpensive is preferable, but other metals such as gold and silver having a high reflectance in the near infrared region can also be preferably used.

When the recording medium of the present invention is a tape-shaped recording medium, it is preferable to use a lubricant for the optical recording layer. When a tape-shaped recording medium is run in a series of manufacturing processing steps, for example, a slitting step or a recording / reproducing apparatus, the lubricant may damage the optical recording layer and the like due to contact with the tape device or contact between the tape front and back. Occurs.
The binder dust becomes a very serious problem such as being caught between the device and the tape, further damaging the tape surface, adhering to the surface of the optical recording layer, and causing noise during signal input / output. Therefore, the slipping agent is used for suppressing the damage of the tape and the generation of binder debris generated during the tape running, and for improving the tape running property.

Examples of preferably used lubricants include polyorganosiloxanes disclosed in JP-B-53-242 and US Pat. No. 4,275,14.
A higher fatty acid amide as described in the specification of No. 6,
JP-B-58-33541, UK Patent No. 927,4
No. 46 or higher fatty acid esters (esters of fatty acids having 10 to 24 carbon atoms and alcohols having 10 to 24 carbon atoms) as disclosed in JP-A-55-126238 and JP-A-58-90633. ), And
Higher fatty acid metal salts as described in U.S. Pat. No. 3,933,516, and JP-A-58-505.
No. 34, esters of linear higher fatty acids and linear higher alcohols,
And higher fatty acid-higher alcohol esters containing a branched alkyl group as described in JP-A-08115.8.

Also, natural waxes such as candelilla wax, carnauba wax, ouriculi wax, rice wax, sugar wax, wood wax, beeswax, whale wax, china insect wax, shellac wax, montan wax and the like can be used as the slip agent. It can be preferably used.

When the optical recording layer of the tape-shaped recording medium contains a lubricant, the content is not particularly limited.
In order to exhibit sufficient scratch resistance and slipperiness, 1 to 500
mg / m ² , and preferably 3 to 200 mg / m ^2.
m ² , particularly preferably 5 to 100 mg / m ² .

In the recording medium of the present invention, various additives can be added to the layer containing the lubricant. For example, monobasic fatty acids having 10 to 22 carbon atoms (saturated, unsaturated, including Li, Na, K, Cu salts), 2-2
A mono- to hexavalent alcohol having 2 carbon atoms (saturated,
Unsaturated alcohols), alkoxy alcohols having 12 to 22 carbon atoms (including saturated and unsaturated), 12 to 22
Esters of monobasic fatty acids having 5 carbon atoms (saturated,
(Including unsaturated), and fatty acid amides having 8 to 22 carbon atoms. Specific examples of these compounds include lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, oleic acid, linolenic acid, butyl stearate, octyl stearate, isooctyl stearate, amyl stearate, butoxyethyl stearate. Oleyl alcohol, lauryl alcohol and the like.

In the present invention, when a layer containing a lubricant is formed, the lubricant can be used by dispersing or dissolving it in a coating solution used for forming each layer. The solvent for dispersing or dissolving the lubricant may be any solvent that does not deteriorate the dispersion stability or the solubility of the lubricant. For example, water, water containing various surfactants, alcohols (methanol, Ethanol, isopropanol, butanol, etc.), ketones (acetone, methyl ethyl ketone, cyclohexanone, etc.), esters (methyl, ethyl, propyl, butyl ester such as acetic acid, formic acid, oxalic acid, maleic acid, succinic acid, etc.), hydrocarbons (Hexane, cyclohexane, etc.), halogenated hydrocarbons (methylene chloride, chloroform, carbon tetrachloride, etc.), aromatic hydrocarbons (benzene, toluene, xylene, benzyl alcohol, benzoic acid, anisole, etc.), amides (dimethyl Formamide, dimethylacetamide, - such as methylpyrrolidone), ethers (diethyl ether, dioxane, tetrahydrofuran, etc.), ether alcohols such as propylene glycol monomethyl ether,
Glycerin, diethylene glycol, dimethyl sulfoxide and the like. Among them, water, water containing various surfactants, alcohols, ketones, and esters are preferable.

In the recording medium of the present invention, the optical recording layer preferably has a reflectance of 15% or more and a transmittance of 30% or less with respect to light used for recording or reproduction. If the reflectivity is low, the read signal is weak and the C / N is low. When the absorption transmittance is high, the recording sensitivity is low.

The layers such as the optical recording layer of the present invention are formed on a support in a predetermined order and a predetermined thickness. As a method for forming each of the above-mentioned layers on the support, there is a method in which a coating solution containing the components of each of the layers is applied, and the layers are sequentially or simultaneously formed. Examples of the method for forming each layer on a disk-shaped support include methods such as spin coating, slide coating, curtain coating, extrusion coating, wire bar coating, gravure coating, and spray coating. .

As a method of applying each layer on a tape-shaped support, a thin layer can be applied and a sufficiently uniform coating film can be formed, particularly from the viewpoint of productivity and film thickness accuracy. As a method, a coating method using a slide coater, a curtain coater, an extrusion coater, a wire bar coater, or a gravure coater, which is widely used in the production of photographic light-sensitive materials, is preferable. The application of each layer can be performed one by one using a slide coater, curtain coater, or extrusion coater, or a plurality of layers can be simultaneously applied. The coating speed can be selected in a wide range, for example, from 1 meter to 1000 meters per minute, but is preferably from 10 meters to 200 meters per minute, which facilitates maintaining uniformity of the coated surface quality and stability of the coating speed.

In the present invention, the coating liquid prepared when each of the above optical recording layers is formed by coating includes water, an organic solvent,
Alternatively, the mixture is prepared by dissolving or dispersing the material to be applied to these mixtures. For example, as a solvent when applying a mixture mainly composed of a pigment and a polymer compound as a binder, ketones (eg, methyl ethyl ketone, cyclohexanone, acetone), alcohols (eg, ethanol, butanol, cyclohexanol, diacetone) Alcohol, 2,2,3,3-tetrafluoro-1-propanol), halogenated hydrocarbons (dichloromethane, 1,2-dichloroethane) and the like.
The viscosity of the coating solution is preferably from 0.5 to 1000 cP, particularly preferably from 0.5 to 100 cP in order to apply a thin layer at a high speed.
Also, in order to improve coating properties, a surfactant is added to the coating solution,
A thickener is also used as a crystal nucleating agent and a gelling agent for suppressing uneven flow due to drying air after application, and preferably a polyfunctional compound for covalently crosslinking a polymer chain (for example, alkylene diisocyanates). , Dichlorotriazines, bisvinylsulfones, etc.) can also be added.

In order to stably form the optical recording layer on the support by applying a coating solution, an undercoat layer may be formed on the support in advance, and then each layer may be formed. The provision of the undercoat layer is preferable because the adhesion between the support and the optical recording layer is improved and peeling and cissing can be prevented. The composition of the undercoat layer is preferably a component having an affinity for a coating solution for forming the optical recording layer. In particular, it is preferably formed by applying a polymer binder. Further, a metal (such as aluminum) may be deposited.

Further, by applying a coating solution on the support,
In order to stably form the optical recording layer, the dye and the binder may be connected by a covalent bond. For example, it is preferable to use a reactive dye as a coloring matter and use a polymer containing a hydroxyl group or an amino group such as a cellulose polymer or gelatin as a binder. Alternatively, it is preferable to apply a mixture of a dye having a hydroxyl group or an amino group and a binder having a hydroxyl group or an amino group in the presence of a crosslinking agent such as diisocyanate.

When the support is in the form of a tape, excessive charging of the web in a manufacturing process thereof, for example, in a process of applying an organic solvent, is not desirable because it may cause uneven coating or risk of ignition due to discharge. Furthermore, even in the slitting process where the tape is cut, the cutting waste generated at the time of cutting adheres to the tape, and especially when the tape is thin, adhesion of the tape to each other due to static electricity causes serious jamming during running. Cause problems. Therefore, an antistatic layer can be appropriately provided. The antistatic layer may be on the optical recording layer side or the reflective surface, and may be an undercoat layer in the optical recording layer.

For this reason, when the recording medium of the present invention is a tape-shaped recording medium, it is desirable to impart an antistatic function to the tape. The antistatic function required for a tape-shaped recording medium includes a surface resistance value SR and a charge leakage speed. The surface resistance is usually log (SR) 1
0 or less, preferably 8 or less, and as a charge leakage rate, the charge half-life Th when applying 8 KV is usually 60 seconds or less,
Preferably it is 10 seconds or less.

The laser applied to the recording medium of the present invention is a solid laser (160 nm) such as YAG, a gas laser such as an argon laser (488 nm), a helium-neon laser (633 nm), or a semiconductor laser (for example, 830 nm, 780 nm, 680 nm, 635
A laser such as nm (nm, 410 nm) can be appropriately selected according to the wavelength of the dye in the optical recording layer for recording or reproducing a signal.

The laser power for recording a signal is preferably 2 mW or more, and the laser power for reading a signal is preferably 1 mW or less.

A semiconductor laser is preferable in that the device can be miniaturized. A preferable example is a 780 nm semiconductor laser, which can be written with a power of 6 to 15 mW.
reading with a power of less than mW.

The beam diameter is preferably about 0.4 to 2 μm. The relative linear velocity between the recording medium and the laser beam is 1-2
0 m / sec, preferably 5 to 15 m / sec.

Next, the magnetic layer of the recording medium of the present invention will be described in detail. The magnetic layer is preferably provided with an undercoat layer, an optical recording layer, and an intermediate layer in this order on a support, and provided on the intermediate layer. The undercoat layer usually has a thickness of 0.01 to
1 μm.

The ferromagnetic powder used for the magnetic layer of the present invention includes γ-Fe ₂ O ₃ and Co-containing (adhered, denatured, doped).
Γ-Fe ₂ O ₃ , Fe ₃ O ₄ , Co-containing (deposited,
Metamorphic, doped) Fe ₃ O ₄ , γ-FeO _x , Co-containing (adhered, metamorphic, doped) γ-FeOx (x = 1.3
Known ferromagnetic powders such as 3 to 1.50), CrO ₂ , hexagonal ferrite powder, and ferromagnetic metal powder can be used.

The ferromagnetic metal powder used in the present invention is not particularly limited, but the effect is particularly remarkable when a ferromagnetic metal powder (including an alloy) containing iron, cobalt or nickel is used. The specific surface area is usually 35 m ² / g or more, and the coercive force is usually 63200
~ 237000A / m, more preferably 102700 ~
It is preferable to use a ferromagnetic metal powder of 142200 A / m or more. As a detailed example of the ferromagnetic metal powder, a metal content in the ferromagnetic metal powder is 60% by weight or more, and 70% by weight or more of the metal content is at least one type of ferromagnetic metal or alloy (eg, Fe). , Co, Ni, F
e-Co, Fe-Ni, Co-Ni, Co-Ni-F
e), and other components (eg, Al, Si,
S, Sc, Ti, V, Cr, Mn, Cu, Zn, Y, M
o, Rh, Pd, Ag, Sn, Sb, Te, Ba, T
a, W, Re, Au, Hg, Pb, Bi, La, Ce,
Alloys that may contain Pr, Nd, B, and P), iron nitride, iron carbide, and the like. The ferromagnetic metal may contain a small amount of water, hydroxide or oxide, an alkali metal element (Na, K, etc.), an alkaline earth metal element (Mg, C
a, Sr). Methods for producing these ferromagnetic metal powders are already known, and ferromagnetic metal powders, which are typical examples of the ferromagnetic powder used in the present invention, can be produced according to these known methods.

That is, as an example of a method for producing a ferromagnetic metal fine powder, the following method can be mentioned. (A) a method of reducing a complex organic acid salt (mainly oxalate) with a reducing gas such as hydrogen; and (b) reducing iron oxide with a reducing gas such as hydrogen to obtain Fe or Fe—Co particles. (C) a method of thermally decomposing a metal carbonyl compound, (d) a method of adding a reducing agent such as sodium borohydride, hypophosphite or hydrazine to an aqueous solution of a ferromagnetic metal, and (e). A method for separating ferromagnetic metal powder from mercury after electrolytic fermentation using a mercury cathode,
(F) A method of evaporating a metal in a low-pressure inert gas to obtain a fine powder. When a ferromagnetic powder is used, its shape is not particularly limited, but usually it is acicular, granular, dice-like, rice-granular. And a plate-like thing is used. The specific surface area (S _BET ) of the ferromagnetic metal powder is preferably 40 m ² / g or more, and more preferably 45 m ² / g or more.

The coercive force (Hc) of these ferromagnetic metal powders is more preferably 79000 to 158000 A / m. Further, σs of these ferromagnetic materials is preferably 100 to 200 emu / g. The crystallite size is preferably from 150 to 300 °.
Examples of these ferromagnetic metal powders are described in JP-A-53-7039.
7, JP-A-58-119609, JP-A-58-13
No. 0435, JP-A-59-80901, JP-A-59-80901
No. 16903, JP-A-59-41453, JP-B-61
-37761, U.S. Pat. No. 4,447,264, U.S. Pat. No. 4,791,021, and U.S. Pat. No. 4,931,198.

The magnetic layer of the present invention can contain an additive such as carbon black. As the carbon black used for the magnetic layer, furnace black for rubber, thermal for rubber, black for color, acetylene black and the like can be used. These carbon blacks are used for the purpose of improving the durability of the tape, such as an antistatic agent, a light shielding agent, a friction coefficient adjusting agent, and the like. Specific examples of abbreviations of these carbon blacks in the United States are as follows: SAF, ISAF, IISAF, T, H
AF, SPF, FF, FEF, HMF, GPF, AP
F, SRF, MPF, ECF, SCF, CF, FT, M
There are T, HCC, HCF, MCF, LFF, RCF and the like, and those classified in D-1765-82a of the US ASTM standard can be used. The average particle size of these carbon blacks used in the present invention is 5-1.
000nm (electron microscope), nitrogen adsorption method specific surface area is 1 ~
800 m ² / g, pH is 4 to 11 (JIS K-62)
21-1982 method), oil absorption of dibutyl phthalate (DBP) is 10-800 ml / 100 g (JIS K-6
221-1982 method). Car used in the present invention
The size of the carbon black is 5 to 100 nm for the purpose of lowering the surface electric resistance of the coating film, and 50 to 1000 nm for controlling the strength of the coating film.
Use Bon Black. For the purpose of controlling the surface roughness of the coating film, finer carbon black (less than 100 nm) is used for smoothing to reduce spacing loss.
Coarse carbon black (100 nm or more) is used for the purpose of roughening and lowering the friction coefficient. As described above, the type and amount of carbon black are properly used depending on the purpose required for the recording medium. Further, these carbon blacks may be surface-treated with a dispersant described later or grafted with a resin for use. In addition, a carbon black which is treated at a furnace temperature of 2000 ° C. or more to produce carbon black and a part of the surface of which is graphitized can also be used. Also, hollow carbon black can be used as a special carbon black.

In the case of a magnetic layer, these carbon blacks are used in an amount of 0.1 to 30 parts by weight per 100 parts by weight of the ferromagnetic metal powder.
It is desirable to use parts by weight. In this case, it is desirable to use 20 to 400 parts by weight with respect to 100 parts by weight of a resin described later. Carbon black which can be used in the present invention can be referred to, for example, "Carbon Black Handbook", edited by Carbon Black Association (issued in 1971). Examples of these carbon blacks are described in U.S. Pat.
257, U.S. Pat. No. 4,614,685, JP-A-61-9
No. 2424 and JP-A-61-99927.

The abrasive used in the magnetic layer of the present invention is used to improve the durability of the magnetic tape and the head cleaning effect of the VTR, and is generally a material having an abrasive action or a polishing action. γ-alumina,
α, γ-alumina Fused alumina, silicon carbide, chromium oxide, cerium oxide, corundum, artificial diamond, diamond, α-iron oxide, garnet, emery (main component: corundum and magnetite), garnet, silica, nitride Silicon, boron nitride, molybdenum carbide, boron carbide, tungsten carbide, titanium carbide, tripoly, diatomaceous earth, dolomite, etc., mainly used in combination with up to 4 types of Mohs hardness of 6 or more . These abrasives have an average particle size of 0.005 to 5 μm, and particularly preferably 0.01 to 2 μm. When diamond is used, it may be used in combination with other abrasives, preferably in a range of 100 to 1000% by weight based on the diamond. In the case of a magnetic layer, these abrasives are added in a range of 0.01 to 20 parts by weight based on 100 parts by weight of the ferromagnetic metal powder. In this case, it is desirable to use 0.01 to 5 parts by weight based on 100 parts by weight of a resin described later. Examples of these are AKP manufactured by Sumitomo Chemical Co., Ltd.
1, AKP15, AKP20, AKP30, AKP5
0, AKP80, Hit50, Hit100 and the like. These are described in JP-B-52-28642, JP-B-49-39402, JP-A-63-98828,
U.S. Pat. No. 3,687,725, U.S. Pat.
No. 3,041,196, US Pat.
6, U.S. Pat. No. 3,630,910, U.S. Pat.
12, U.S. Pat. No. 4,117,190, British Patent 1145
349, West German Patent 853211 and the like.

As the binder used in the magnetic layer of the present invention, conventionally known thermoplastic resins, thermosetting resins, reactive resins, electron beam curable resins, ultraviolet ray curable resins, visible ray curable resins and the like can be used. Is used. The thermoplastic resin has a softening temperature of 150 ° C or less and an average molecular weight of 10
000 to 300,000, and a polymerization degree of about 50 to 2,000, and more preferably about 200 to 600. For example, vinyl chloride vinyl acetate copolymer, vinyl chloride copolymer, vinyl chloride vinyl acetate vinyl alcohol copolymer,
Vinyl chloride vinyl alcohol copolymer, vinyl chloride vinylidene chloride copolymer, vinyl chloride acrylonitrile copolymer, acrylate acrylonitrile copolymer,
Acrylate vinylidene chloride copolymer, acrylate styrene copolymer, methacrylate acrylonitrile copolymer, methacrylate vinylidene chloride copolymer, methacrylate styrene copolymer, urethane elastomer, nylon-silicone Resin, nitrocellulose-polyamide resin, polyvinyl fluoride, vinylidene chloride acrylonitrile copolymer, butadiene acrylonitrile copolymer, polyamide resin, polyvinyl butyral, cellulose derivative (cellulose acetate butyrate, cellulose diacetate) -Cellulose triacetate, cellulose propionate, nitrocellulose, ethylcellulose, methylcellulose
, Propylcellulose, methylethylcellulose, carboxymethylcellulose, acetylcellulose, etc.),
Styrene butadiene copolymer, polyester resin, polycarbonate resin, chlorovinyl ether acrylate copolymer, amino resin, various synthetic rubber-based thermoplastic resins, and mixtures thereof are used. Examples of these resins are described in JP-B-37-6877 and JP-B-39-1.
No. 2528, Japanese Patent Publication No. 39-19282, Japanese Patent Publication No. 40-
No. 5349 No. 40-20907, No. 41-
9463, JP-B-41-14059, JP-B-41-140-
No. 16985 JP-B-42-6428, JP-B-42-
No. 11621, JP-B-43-4623, JP-B-43-
No. 15206 No. 44-2889, No. 44-
17947, JP-B-44-18232, JP-B-45
No. 14020, No. 45-14500, No. 4
Nos. 7-18573, JP-B-47-22063, JP-B-47-22264, JP-B-47-22068, JP-B-47-22069, JP-B-47-22070, JP-B-47-27886, and JP-A-57-27886. -13352
1, JP-A-58-137133, JP-A-58-1665
33, JP-A-58-222433, JP-A-59-586.
42 et al., US Pat. No. 4,571,364, US Pat.
No. 530, for example.

The thermosetting resin or the reactive resin has a molecular weight of 200,000 or less in the state of a coating solution.
By heating and humidifying after drying, the molecular weight becomes infinite due to reactions such as condensation and addition. Among these resins, those which do not soften or melt before the resin is thermally decomposed are preferable. Specifically, for example, phenol resin, phenoxy resin, epoxy resin, polyurethane resin, polyester resin, polyurethane polycarbonate resin, urea resin, melamine resin, alkyd resin, silicone resin, acrylic reaction resin (electron beam curing resin), epoxy -Polyamide resin, nitrocellulose melamine resin, mixture of high molecular weight polyester resin and isocyanate prepolymer, mixture of methacrylate copolymer and diisocyanate prepolymer, mixture of polyester polyol and polyisocyanate, urea formaldehyde resin, low molecular weight A mixture of glycol / high molecular weight diol / triphenylmethane triisocyanate, a polyamine resin, a polyimine resin, a mixture thereof and the like.
Examples of these resins are described in JP-B-39-8103, JP-B-40-9779, JP-B-41-7192, and JP-B-sho-4.
No. 1-8016 No. 41-14275, No. 4
No. 2-18179, JP-B-43-12081, JP-B-44-28023 JP-B-45-14501, JP-B-45-24902, JP-B-46-13103, JP-B-47-22265 and JP-B-47-22066 issue,
JP-B-47-22067 and JP-B-47-22072
No., JP-B-47-22073, JP-B-47-2804
No. 5, JP-B-47-28048, JP-B-47-289
No. 22, etc. These thermoplastic, thermosetting resins and reactive resins have carboxylic acid (COOM), sulfinic acid, sulfenic acid, sulfonic acid (SO ₃ M), and phosphoric acid (PO (OM)) as functional groups other than the main functional groups.
(OM)), phosphonic acid, sulfuric acid (OSO ₃ M), and acidic groups such as ester groups thereof (M is H, an alkali metal,
An alkaline earth metal, a hydrocarbon group), an amino acid; an aminosulfonic acid, a sulfuric acid or phosphoric acid ester of an amino alcohol, an amphoteric group such as an alkyl betaine type, an amino group,
Imino group, imide group, amide group, etc., hydroxyl group, alkoxyl group, thiol group, alkylthio group, halogen group (F, Cl, Br, I), silyl group, siloxane group, epoxy group, isocyanato group, cyano group , A nitrile group, an oxo group, an acrylic group, and a phosphine group.
Within each species, each functional group is 1 × 10 ^-6 per g of resin
It preferably contains eq to 1 × 10 ^-2 eq.

These binders may be used alone or in combination, and other additives may be added. The mixing ratio of the ferromagnetic metal powder and the binder in the magnetic layer is in the range of 5 to 300 parts by weight of the binder per 100 parts by weight of the ferromagnetic metal powder. Additives include dispersants, lubricants, abrasives, antistatic agents, antioxidants, solvents and the like.
Examples of the polyisocyanate used in the magnetic layer of the present invention include tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, and naphthylene. 1,
5-diisocyanate, o-toluidine diisocyanate
, Isophorone diisocyanate, triphenylmethane triisocyanate, isophorone diisocyanate and other isocyanates, and products of such isocyanates and polyalcohols, and isocyanates Polyisocyanates of 2 to 10 mer produced by condensation of the compounds, and products of polyisocyanate and polyurethane, whose terminal functional groups are isocyanates, can be used.
The average molecular weight of these polyisocyanates is 100 to 2
0000 are preferred. These polyisocyanates
The commercially available trade names of Coronate L, Coronate HL, Coronate 2030, Coronate 203
1, Millionate MR, Millionate MTL (manufactured by Nippon Polyurethane Co., Ltd.), Takenet D-102, Takenet D
-110N, Takenate D-200, Takenate D-
202, Takenate 300S, Takenate 500 (manufactured by Takeda Pharmaceutical Co., Ltd.), Sumidur T-80, Sumidur 44
S, Sumidur PF, Sumidur L, Sumidur N, Desmodur L, Desmodur IL, Desmodur N, Desmodur HL, Desmodur T6
5, Desmodule 15, Desmodule R, Desmodule RF, Desmodule SL, Desmodule Z4
273 (manufactured by Sumitomo Bayer Co., Ltd.), and these can be used alone or in combination of two or more by utilizing the difference in curing reactivity. Compounds having a hydroxyl group (butanediol, hexanediol, polyurethane having a molecular weight of 1,000 to 10,000, water, etc.), an amino group (monomethylamine, dimethylamine, trimethylamine, etc.) or metal oxides for the purpose of accelerating the curing reaction. A catalyst such as a product catalyst or a catalyst such as iron acetylacetonate can be used in combination. It is desirable that these compounds having a hydroxyl group or an amino group are polyfunctional. These polyisocyanates are used in a magnetic layer, both in a binder resin and in a polyisocyanate.
Preferably, it is used in an amount of 2 to 70 parts by weight, more preferably 5 to 50 parts by weight, per 100 parts by weight of the total amount. Examples of these are disclosed in JP-A-60-131622 and JP-A-61-74138.

The powdery lubricant used for the magnetic layer of the present invention includes graphite, molybdenum disulfide, boron nitride, graphite fluoride, calcium carbonate, barium sulfate, silicon oxide, titanium oxide, zinc oxide, tin oxide, and the like. Inorganic fine powder such as tungsten disulfide, acrylic styrene resin fine powder, benzoguanamine resin fine powder, melamine resin fine powder,
Resin fine powders such as polyolefin resin fine powder, polyester resin fine powder, polyamide resin fine powder, polyimide resin fine powder, and polyfucker ethylene resin fine powder.

As the organic compound-based lubricant, silicone oil (dialkyl polysiloxane, dialkoxy polysiloxane, phenyl polysiloxane, fluoroalkyl polysiloxane (KF96, KF69 manufactured by Shin-Etsu Chemical Co., Ltd.)
Etc.), fatty acid-modified silicone oil, fluorine alcohol
, Polyolefin (polyethylene wax, polypropylene, etc.), polyglycol (ethylene glycol, polyethylene oxide wax, etc.), tetrafluoroethylene oxide wax, polytetrafluoroglycol
Perfluoroalkyl ether, perfluoro fatty acid, perfluoro fatty acid ester, perfluoroalkyl sulfate, perfluoroalkyl sulfonate, perfluoroalkyl benzene sulfonate, perfluoroalkyl phosphate, etc. And compounds containing silicon, alkyl sulfate, alkyl sulfonate, alkyl phosphonate triester,
Organic acids and organic acid ester compounds such as alkyl phosphonic acid monoesters, alkyl phosphonic acid diesters, alkyl phosphate esters, and succinate esters; triazaindolizine, tetraazaindene, benzotriazole, benzotriazine, benzodiazole, EDTA, etc. Heterocyclic compounds containing nitrogen and sulfur, C10-4
0 monobasic fatty acid and any of monovalent alcohols having 2 to 40 carbon atoms, divalent alcohols, trivalent alcohols, tetravalent alcohols, and hexavalent alcohols Fatty acid esters composed of at least one or two or more carbon atoms
Fatty acid esters comprising mono- to hexavalent alcohols having a total of 11 to 70 carbon atoms in total with at least one monobasic fatty acid and the number of carbon atoms of the fatty acid, a fatty acid or fatty acid having 8 to 40 carbon atoms Amides, fatty acid alkylamides, and aliphatic alcohols can also be used.

Specific examples of these compounds include butyl caprylate, octyl caprylate, ethyl laurate, butyl laurate, octyl laurate, ethyl myristate, butyl myristate, octyl myristate, 2-ethylhexyl myristate, Ethyl palmitate, butyl palmitate, octyl palmitate, 2 ethylhexyl palmitate, ethyl stearate, butyl stearate, isobutyl stearate, octyl stearate, 2 ethylhexyl stearate, amyl stearate, isoamyl stearate, 2 stearic acid
Ethylpentyl, 2-hexyldecyl stearate, isotridecyl stearate, stearic acid amide, alkyl stearate, butoxyethyl stearate,
Anhydrosorbitan monostearate, anhydrosorbitan distearate, anhydrosorbitan tristearate, anhydrosorbitan tetrastearate
G, oleyl oleate, oleyl alcohol, lauryl alcohol, montan wax, carnauba wax,
It can be used alone or in combination.

As the lubricant used in the magnetic layer of the present invention, a so-called lubricating oil additive can be used alone or in combination, and antioxidants (alkylphenol, benzotriazine, etc.) used as rust preventives can be used. , Metal chelators such as tetraazaindene, sulfamide, guanidine, nucleic acid, pyridine, amine, hydroquinone, EDTA), rust inhibitors (naphthenic acid, alkenyl succinic acid, phosphoric acid, dilauryl phosphate, etc.), oily agents (Rapeseed oil, lauryl alcohol, etc.), extreme pressure agent (dibenzyl sulfide, tricresyl phosphate, tributyl phosphite, etc.), detergent / dispersant, viscosity index improver, pour point depressant, foamer Agents. These lubricants are added in the range of 0.01 to 30 parts by weight based on 100 parts by weight of the binder. These are described in JP-B-43-23889 and JP-B-4
8-24041, JP-B-48-18482, JP-B-44-18221, JP-B-47-28043, JP-B-57-56132, JP-A-59-8136, JP-A-59-8136.
No. 9-8139, JP-A-61-85621, U.S. Pat. No. 3,423,233, U.S. Pat. No. 3,470,235, U.S. Pat. No. 3,492,235, U.S. Pat. No. 3,497,411, U.S. Pat. 3634253,
U.S. Pat. No. 3,642,539, U.S. Pat.
No. 4,350,031 and U.S. Pat.
4, U.S. Pat. No. 4,552,794, IBM Technology Disclosure Bulletin (IBM Techn.
Iical Disclosure Bulletin)
Vol. 9, No7, p779 (December 1966),
ELEKTRONIK 1961 N
o12, p380, Handbook of Chemistry, Application, p954-96
7, 1980, published by Maruzen shares.

The dispersing agent and dispersing agent used in the magnetic layer of the present invention include caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, elaidic acid, linoleic acid, and linolenic acid. 2 carbon atoms such as acid, stearolic acid, behenic acid, maleic acid, phthalic acid, etc.
40 to 40 fatty acids (R ₂ COOH, R ₂ has 1 to 3 carbon atoms)
9 alkyl groups, phenyl groups, aralkyl groups) and alkali metals (Li, Na, K, NH) of the above fatty acids
₄ ^+, etc.) or alkaline earth metals (Mg, Ca, Ba
Etc.), metal soap (copper oleate) composed of Cu, Pb, etc., fatty acid amide; lecithin (soybean oil lecithin) and the like are used. In addition, high-grade alcohol having 4 to 40 carbon atoms-
(Butanol, octyl alcohol, myristyl alcohol, stearyl alcohol) and their sulfates, sulfonic acids, phenylsulfonic acids, alkylsulfonic acids, sulfonic esters, phosphoric monoesters, phosphoric diesters, Phosphoric acid triesters, alkylphosphonic acids, phenylphosphonic acids, amine compounds and the like can also be used. In addition, polyethylene glycol, polyethylene oxide, sulfosuccinic acid, metal sulfosuccinate, sulfosuccinate, and the like can also be used. One or more of these dispersants are usually used, and one dispersant is
It is added in the range of 0.005 to 20 parts by weight based on 00 parts by weight. These dispersants may be used in advance by applying them to the surface of the ferromagnetic metal powder or nonmagnetic fine powder, or may be added during the dispersion. Such materials are disclosed, for example, in JP-B-39-28369, JP-B-44-17945,
JP-B-44-18221, JP-B-48-7441,
JP-B-48-15001, JP-B-48-15002
No., JP-B-48-16363, JP-B-49-3940
2, U.S. Pat. Nos. 3,387,993 and 3,347,0021.

The antifungal agent used in the magnetic layer of the present invention is 2
-(4-thiazolyl) -benzimidazole, N- (fluorodichloromethylthio) -phthalimide, 10,1
0'-oxybisphenoxalcin, 2,4,5,6 tetrachloroisophthalonitrile, P-tolyldiiodomethylsulfone, triiodoallyl alcohol, dihydroacetoic acid, mercury phenyloleate, bis (tributyltin) oxide And saltyl anilide. Such a substance is shown in, for example, "Microbial Disaster and Prevention Technology", Engineering Books, 1972, "Chemistry and Industry", 32, 904 (1979).

Examples of antistatic agents other than carbon black used in the magnetic layer of the present invention include graphite, modified graphite, carbon black graft polymer, tin oxide-antimony oxide, tin oxide, titanium oxide-tin oxide-antimony oxide, Nonionic surface activity such as alkylene oxide, glycerin, glycidol, polyhydric alcohol, polyhydric alcohol ester, alkylphenol EO adduct, etc. Agent;
Cationic surfactants such as higher alkylamines, cyclic amines, hydantoin derivatives, amidoamines, esteramides, quaternary ammonium salts, pyridine and other heterocycles, phosphoniums and sulfoniums; carboxylic acids, sulfonic acids, phosphonic acids, phosphoric acids , Sulfate group,
Anionic surfactants containing acidic groups such as phosphonates and phosphates; amino acids; aminosulfonic acids, sulfuric acid or phosphates of amino alcohols, and amphoteric surfactants such as alkyl betaines are used. .
Some examples of surfactant compounds that can be used as an antistatic agent are described in JP-A-60-28025, U.S. Pat.
Nos. 1623, 2240472, 2288226
Nos. 2,676,122, 2,676,924,26
No. 76975, No. 2691566, No. 2727860
Nos. 2,730,498, 2,742,379, and 27
No. 39891, No. 3068101, No. 3158484
No., No. 3201253, No. 32010191, No. 32
No. 94540, No. 3415649, No. 3441413
No., No. 3424654, No. 3475174, No. 35
No. 45974, West German Patent Publication (OLS) 1942665
Ryohei Oda et al., "Synthesis of Surfactant and Its Application" (Maki Shoten, 1972 edition); W. Beili, Sir
Fuss Active Ages "(Inter-Science Publication Corporation, 1985 edition); P. By Shisley, "Encyclopedia of Surfactive Agents, Volume 2"
(Chemical Publish Campani, 1964 edition); Handbook of Surfactants, 6th printing (Sangyo Tosho Co., Ltd., December 20, 1966); Hideo Marumo, "Antistatic Agent", Koshobo (1)
968). These surfactants may be added alone or as a mixture. The amount of these surfactants used in the recording medium is usually 0.01 to 10 parts by weight per 100 parts by weight of the ferromagnetic metal powder. These are used as antistatic agents, but sometimes for other purposes, such as dispersion, improved magnetic properties, improved lubricity, coating aids, wetting agents, curing accelerators,
It may be applied as a dispersion promoter.

As the organic solvent used in the dispersion, kneading and coating of the present invention, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, isophorone and tetrahydrofuran in any ratio; methanol, ethanol Alcohols such as acetic acid, propanol, butanol, isobutyl alcohol, isopropyl alcohol and methylcyclohexanol; methyl acetate;
Ester systems such as ethyl acetate, butyl acetate, isobutyl acetate, isopropyl acetate, ethyl lactate, and glycol monoethyl ether; ethers such as diethyl ether, tetrahydrofuran, glycol dimethyl ether, glycol monoethyl ether, and dioxane Tar system (aromatic hydrocarbon) such as benzene, toluene, xylene, cresol, chlorobenzene, styrene; methylene chloride, ethylene chloride, carbon tetrachloride, chloroform, ethylene chlorohydrin, dichlorobenzene, etc. Chlorinated hydrocarbons, N, N-dimethylformaldehyde, hexane and the like can be used. These solvents are generally used in two or more kinds at an arbitrary ratio. In addition, trace amounts of impurities (polymerization of the solvent itself, water,
Raw material components).

These solvents are used in an amount of 100 to 20,000 parts by weight based on 100 parts by weight of the total solid content of the magnetic liquid and the undercoat liquid. The preferred solid content of the magnetic liquid is 10 to 40% by weight. An aqueous solvent (water, alcohol, acetone, etc.) can be used instead of the organic solvent. The magnetic layer is formed by dissolving in an organic solvent any combination of the above compositions and the like, and coating, drying, and orienting on a support as a coating solution.
When used as a tape, the thickness of the support is usually
The thickness is about 2.5 to 100 μm, preferably about 3 to 70 μm. In the case of a disc or card, the thickness is 0.
It is about 03 to 10 mm, and in the case of a drum, it can be used in a cylindrical shape. Polyesters such as polyethylene terephthalate, polyethylene naphthalate, etc.
In addition to polyolefins such as polypropylene, cellulose derivatives such as cellulose triacetate and cellulose diacetate, vinyl resins such as polyvinyl chloride, plastics such as polycarbonate, polyimide, polyamide and polysulfone. Metals such as aluminum and copper, and ceramics such as glass can also be used. Prior to coating, these supports may be subjected to corona discharge treatment, plasma treatment, priming treatment, heat treatment, dust removal treatment, metal deposition treatment, and alkali treatment. For these supports, for example,
West German Patent 3338854A, Japanese Patent Laid-Open No. 59-116926
No., JP-A-61-129731, U.S. Pat.
No. 68; Yukio Mitsuishi, Textile and Industry, Vol. 31, p. 50
55, 1975 and the like. In the case of video tapes and the like, the center surface average surface roughness of these supports is 0.00
It is preferably 1 to 0.5 μm (cutoff value 0.25 mm). The Young's modulus (F5 value) of these supports is ^{2 to} 30 kg / mm ² (1 in both the width direction and the longitudinal direction) depending on the purpose.
(Kg / m ² = 9.8 Pa) can be selected.

The method of dispersion and kneading is not particularly limited, and the order of addition of each component (resin, powder, lubricant, solvent, etc.)
The addition position during dispersion / kneading, the dispersion temperature (0 to 80 ° C.), and the like can be appropriately set. For the preparation of magnetic paints and various paints, conventional kneading machines such as a two-roll mill,
Three roll mill, ball mill, pebble mill, tron mill, sand grinder, Tsegvar
i) Attritors, high-speed impellers, dispersers, high-speed stone mills, high-speed impact mills, dispersers, kneaders, high-speed mixers, ribbon blenders, coniders, intensive mixers, tumblers, Blenders, dispersers, homogenizers, single-screw extruders, twin-screw extruders, and ultrasonic dispersers can be used. Usually, a plurality of these dispersing and kneading machines are provided for dispersing and kneading, and the treatment is continuously performed. For details of the technique relating to kneading and dispersion, see T.S. C. PATON (Tec.
Patton) "Paint Flow and Pigm
ent Dispersion "(Paint Flow
And Pigment Day Spurgeon) 1964 J
published by John Wiley & Sons (John Willy and Sons) and Shinichi Tanaka, Industrial Materials
25, 37 (1977) and the references cited in the book. In order to efficiently promote dispersion and kneading as an auxiliary material for these dispersion and kneading, the equivalent diameter of the sphere is 10 cmφ or more.
Steel balls, steel beads, ceramic beads, glass beads, and organic polymer beads having a diameter of 0.05 mmφ can be used. These materials are not limited to spherical shapes. In addition, U.S. Pat.
It is also described in the specification such as 855156. In the present invention, a magnetic coating material and a coating material can be prepared by kneading and dispersing according to the method described in the above-mentioned book or the cited document of the book.

As a method of applying the above-mentioned coating solution for a magnetic layer on a support, the viscosity of the coating solution is adjusted to 1 to 20,000 centistokes (25 ° C.), and an air doctor coater, a blade coater or the like is used. -Coater, air knife coater, squeeze coater, impregnated coater, reverse roll coater, transfer roll coater, gravure coater, kiss coater, cast coater, spray coater, rod coater , A forward rotation roll coater, a curtain coater, an extrusion coater, a bar coater, a lip coater and the like can be used, and other methods are also possible. Published “Coating Engineering”, page 253-2
This is described in detail on page 77 (issued in 1963, 1963). The order of application of these coating liquids can be arbitrarily selected, and a corona discharge treatment or the like may be performed before application of a desired liquid to improve adhesion to an undercoat layer or a support.

In the present invention, the magnetic layer is provided on the intermediate layer. The intermediate layer is provided on the optical recording layer. Then, the optical recording layer is provided on the support. The middle layer is
The coating solution for the optical recording layer may be applied on the support and applied after drying, or may be provided at the same time while both coating solutions are wet. Further, the magnetic layer may be provided by being applied on the dried intermediate layer provided with the optical recording layer and the intermediate layer, or the respective coating solutions wet the intermediate layer and the magnetic layer on the optical recording layer at the same time. It may be provided between states. Preferably, the optical recording layer, the intermediate layer and the magnetic layer, or the intermediate layer and the magnetic layer are simultaneously provided on the support while their respective coating solutions are wet, so that productivity, adhesion between the layers, and uniformity of the layers can be improved. And so on.

Further, at least one of each of the optical recording layer, the intermediate layer and the magnetic layer may be composed of a plurality of layers.
Also in this case, the same method of forming and applying each layer as described above is applied. The above-mentioned simultaneous multi-layer coating and sequential multi-layer coating are described in, for example, JP-A-57-123532, JP-B-62-37451, JP-A-59-142741, and JP-A-59-165239. It is described in the specification of the gazette.

By such a method, about 1 to about
If necessary, the magnetic liquid applied at about 100 μm is dried in multiple stages at 20 to 130 ° C. while drying the magnetic powder in the layer at a magnetic flux density of 50,000 to 500,000 μT in a desired direction (vertical, longitudinal, width, random, After performing a treatment for orienting the magnetic layer at an angle of, for example, 0.1 to 30
Dry to a thickness of μm. The transport speed of the support at this time is
Usually, the drying is performed at a rate of 10 m / min to 900 m / min. The drying temperature is controlled at 20 ° C. to 130 ° C. in a plurality of drying zones, and the residual solvent amount of the coating film is set to 0.1 to 40 mg / m ² . The recording medium of the present invention may be subjected to surface smoothing if necessary to make the center surface average surface roughness of the magnetic layer 0.001 to 0.3 μm (cutoff 0.25 mm) and cut into a desired shape. To manufacture. In these production methods, it is desirable to continuously perform steps of powder pretreatment / surface treatment, kneading / dispersion, coating / orientation / drying, smoothing treatment, heat treatment, EB treatment, surface polishing treatment, cutting, and winding. . These are disclosed, for example, in Japanese Patent Publication No. 40-23625, Japanese Patent Publication No. 39-28368, Japanese Patent Publication No. 47-38802, and British Patent 119.
No. 1424, JP-B-48-11336, JP-A-Showa 4
9-53631, JP-A-50-112005, JP-A-51-77303, JP-B-52-17404, JP-A-60-70532, JP-A-2-265672
No. 3,473,960, U.S. Pat.
No. 569, U.S. Pat. No. 4,746,542 and the like. The method disclosed in Japanese Patent Publication No. 41-13181 is considered to be a basic and important technique in this field.

After the recording medium having the magnetic layer, the intermediate layer and the optical recording layer formed on the support is cut, the recording medium is wound around a desired plastic or metal reel. It is desirable to burnish and / or clean the recording medium (magnetic layer, edge end surface, base surface) immediately before or before winding. The burnish uses a hard material such as a sapphire blade, a razor blade, a super hard material blade, a diamond blade, or a ceramic blade to scrape off the protrusions on the surface of the recording medium and make the recording medium smooth. The Mohs hardness of these materials is preferably 8 or more, but is not particularly limited as long as protrusions can be removed. The shape of these materials does not need to be a blade in particular, and shapes such as a square shape, a round shape, and a wheel (these materials may be provided around a rotating cylindrical shape) can be used. The cleaning of the recording medium is performed by removing the surface of the recording medium with a non-woven fabric or the like with a magnetic layer surface, an edge end surface,
This is performed by wiping the support surface or the back layer opposite to the magnetic layer side. Examples of such wiping materials include various types of virgin made by Japan Vilene and Toraysee made by Toray Co., Ltd., Exeine, trade name Kimwipe, various types of polishing tape made by Fuji Photo Film, and nonwoven fabric made of nylon nonwoven fabric, polyester nonwoven fabric, rayon nonwoven fabric, Tissue paper and the like such as acrylonitrile nonwoven fabric and blended nonwoven fabric can be used. These are, for example,
39309, JP-B-58-46768, JP-A-56
No. -90429, JP-B-58-46767, JP-A-Showa 6
Also described in JP-A-3-259830 and JP-A-1-201824.

The ferromagnetic metal powder or non-magnetic powder used in the present invention, binders, additives (lubricants, dispersants, antistatic agents, surface treatment agents, carbon black, abrasives, light shielding agents,
Antioxidants, fungicides, etc.), solvents and supports (which may have an undercoat layer) or methods for producing recording media are described in
No. 26890 can also be referred to.

[0095]

EXAMPLES The present invention will be described more specifically with reference to the following examples. It will be readily understood by those skilled in the art that the components, ratios, operation sequences, and the like shown herein can be changed without departing from the spirit of the present invention. Therefore, the present invention should not be limited to the following examples. The parts in the examples are parts by weight. Example 1 The following coating solution for forming an optical recording layer was applied to a 3.5 μm-thick aramid (Ra1n on the optical recording layer forming surface) using a wire bar coater.
m, opposite surface Ra 5 nm) to form a red-sensitive optical recording layer having a dry thickness of 0.2 μm by coating on a support.

The coating solution is sent from a coating solution tank by a feeding pump, and is supplied to a wire bar coater through a filter. The wire bar coater rotates in the same direction as the transport direction of the support, and transfers the coating solution to the support. The diameter of the wire is 0.15mm and the peripheral speed of the wire bar is 20 per minute
m, a coating film having a wet film thickness of 10 μm was obtained. After application, 4
After drying at 0 ° C. and then with hot air at 80 ° C., it was wound up. Optical recording layer forming coating solution: Compound 1 part of red sensitive dye (compound having the following structure) 1 part Compound red sensitive dye 1 part (In the formula (a), R ₁ is an ethyl group, X ⁻ is CF ₃ SO ₃ ⁻ , = 3) IRG-022 (manufactured by Nippon Kayaku Co., Ltd.) 0.1 part

[0097]

Embedded image Cellulose acetate butyrate (CAB) 1.0 part (manufactured by Eastman Chemical Company) Coronate L (manufactured by Nippon Polyurethane Industry Co., Ltd.) 0.2 part Methyl ethyl ketone 150 parts The following coating solution for forming an intermediate layer is prepared, and a magnetic layer is prepared. A coating solution for forming (excluding a curing agent) is uniformly kneaded and dispersed to adjust the viscosity, a curing agent is added, and then both coating solutions are simultaneously coated on the optical recording layer provided on the aramid support.・ Orientation, drying, calendering, cutting, intermediate layer thickness 0.5μ
m, a tape-shaped recording medium having a magnetic layer thickness of 0.2 μm was obtained. Coating solution for forming an intermediate layer: Silica 0.1 μm (average particle diameter) 25 parts Red iron oxide 0.5 μm (average particle diameter) 100 parts Polyester polyurethane (SO ₃ Na group: 3 × 10 ⁻⁴ eq / g) 60 parts Poly Isocyanate (Nippon Polyurethane N2030) 10 parts Methyl ethyl ketone / cyclohexanone = 1/250 parts Coating solution for forming magnetic layer: Ferromagnetic metal powder Hc = 175000 A / m 100 parts Binder (phenoxy resin, PKHH) 3 parts Binder 10 parts (polyester polyurethane) Resin, 1 × 10 ^-4 eq / g containing SO ₃ Na Curing agent (polyisocyanate) 4 parts Carbon black (Vulcan XC72) 5 parts Alumina (average particle diameter 0.1 μm) 1 part Diamond 3 parts (average particle diameter 0) 0.1 μm grade 0-0.25) Oleyl oleate 1 part In palmitic acid 1 part of 2-ethylhexyl stearate 1 part Methyl ethyl ketone / cyclohexanone = 1/1 200 parts Examples 2-3 Example 1, except that changes the optical recording layer thickness was prepared tape-shaped recording medium in the same manner as Example 1.

Example 4 A tape-shaped recording medium was prepared in the same manner as in Example 1, except that the intermediate layer and the magnetic layer were provided on the support opposite to the optical recording layer. Examples 5 to 11 A tape-shaped recording medium was prepared in the same manner as in Example 1, except that the number of diamonds and alumina in the magnetic layer was changed. Example 5 is the same as Example 1.

The carrier information C (dBm), the noise level N (dBm) and the C / N ratio (dB) of the tape-shaped information recording medium prepared as described above were evaluated.
The evaluation conditions were as follows. <Evaluation of tape-shaped optical servo recording> Semiconductor laser: wavelength 680 nm Laser beam diameter: 1 μm Linear velocity: 5 m / sec Recording power: 8 mW Recording frequency: 2.5 MHz Recording duty: 50% Reproduction power: 0.6 mW The number of windings in which the binder of the optical recording layer was melted and scattered at the time of forming pits for> 20 windings was examined. <Head clog> Clogging of magnetic recording / reproducing head in VTR. The number of windings where the output decreased when 20 windings were run for 100 passes each is displayed.

[0100]

[Table 1] Even if the optical recording layer was below the magnetic layer, there was no hindrance to optical recording, and no flying objects were seen. Further, in Example 4 in which the optical recording layer was provided on the side opposite to the magnetic layer side, scattered matters were observed in all the cases.

[0101]

[Table 2] It can be seen that Examples 5 to 7 in which the magnetic layer contains a predetermined amount of diamond are effective for the output of the magnetic layer and the prevention of head clogging. Also, as shown in Example 9, the effect is inferior to that of the above example even when diamond is excessively used. As shown in Example 11, when alumina is sufficiently added to the head clog, the output decreases.

[0102]

The recording medium of the present invention has a structure in which an optical recording layer, an intermediate layer and a magnetic layer are provided in this order on one surface of a support. Since the access speed can be improved and the support has the function of a protective layer of the optical recording layer, there is no adhesion of flying matter from the optical recording layer, and the durability is secured.

Claims (5)

[Claims] 1. A recording medium comprising an optical recording layer, an intermediate layer and a magnetic layer provided on a support in this order. 2. The recording medium according to claim 1, further comprising a back coat layer on a surface opposite to a support provided with an optical recording layer and the like. 3. The magnetic layer has an average particle diameter of 0.1 to 1 μm.
3. The diamond according to claim 1, wherein
A recording medium according to claim 1. 4. An information signal is recorded on a magnetic layer, a servo signal is recorded on an optical recording layer, and a tracking servo signal is detected by scanning in a width direction of the optical recording layer. The recording medium according to any one of claims 3 to 3. 5. The method for producing a recording medium according to claim 1, wherein a coating material for forming an optical recording layer, a coating material for forming an intermediate layer, and a coating material for forming a magnetic layer are applied on a support.